Display device

ABSTRACT

A display device includes a display panel including a substrate and a plurality of insulating layers, a transistor layer, and a light emitting device layer on the substrate, and including a display area in which an image is displayed, the display area including a first display area and a second display area, and a light receiving device positioned behind the display panel and overlapping the first display area. In the display device, the first display area includes at least one non-transmissive area in which transistors and light emitting devices are located, and at least one transmissive area through which external light is transmitted to the light receiving device. The substrate or at least one insulating layer includes at least one hole or at least one uneven portion in a portion overlapping the transmissive area in the first display area.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit and priority to Korean PatentApplication No. 10-2020-0108324, filed in the Republic of Korea on Aug.27, 2020, the entire contents of which are hereby expressly incorporatedby reference for all purposes as if fully set forth into the presentapplication.

BACKGROUND Technical Field

The present disclosure relates to a display device.

Description of the Related Art

With the development of technology, a display device can provide aphotographing function and a proximity detection function in addition toan image display function. Accordingly, the display device can include alight receiving device such as a camera and a proximity sensor.

Since the light receiving device needs to receive light from the frontof the display device, it needs to be installed in a place where thelight receiving is advantageous. Therefore, in the related art, thecamera (camera lens) and the proximity sensor had to be installed so asto be exposed on the front side of the display device. As a result, thebezel of the display device is widened or a notch or hole is formed inthe display area of the display panel, so that a camera lens or aproximity sensor is installed there.

Therefore, as a light receiving device such as a camera or a proximitysensor that performs a predetermined function by receiving the frontlight is provided in the display device, there may be problems in thatthe bezel is enlarged at the front of the display device or that thefront design of the display device is restricted.

SUMMARY OF THE INVENTION

Embodiments of the present disclosure can provide a display device inwhich a light receiving device is positioned behind a display panel sothat the light receiving device that should receive light from the frontis not exposed to the front. Here, for example, the light receivingdevice can include one or more of a camera, a proximity sensor, and thelike.

Embodiments of the present disclosure can provide a display device inwhich light from the front of a display panel can be well transmitted toa light receiving device through a display panel even if the lightreceiving device is positioned behind the display panel.

Embodiments of the present disclosure can provide a display device inwhich a region overlapping a light receiving device in the display panelhas a higher transmittance than other regions.

Embodiments of the present disclosure can provide a display device inwhich a transmittance improving structure is formed in a regionoverlapping a light receiving device in a display panel.

According to aspects of the present disclosure, a display devicecomprises a display panel including a substrate and a plurality ofinsulating layers, a transistor layer, and a light emitting device layeron the substrate, and including a display area in which an image isdisplayed, the display area including a first display area and a seconddisplay area, and a light receiving device positioned behind the displaypanel and overlapping with the first display area.

The number of subpixels per unit area in the first display area issmaller than the number of subpixels per unit area in the second displayarea.

The first display area includes at least one non-transmissive area inwhich transistors of the transistor layer and light emitting devices ofthe light emitting device layer are located, and at least onetransmissive area through which external light is transmitted to thelight receiving device.

The substrate or at least one insulating layer among the plurality ofinsulating layers includes at least one hole or at least one unevenportion in a portion overlapping the one transmissive area.

The one uneven portion can be formed on a rear surface of the substrate,and a portion of the substrate that overlaps the one transmissive areacan include at least one raised rear surface.

The display device can further include a transparent material layerdisposed under the one raised rear surface of the substrate.

At least one uneven portion can be formed on an upper surface of thesubstrate, and a portion of the substrate that overlaps the onetransmissive area can include at least one recessed upper surface.

The substrate can include a first substrate, an interlayer insulatinglayer on the first substrate, and a second substrate on the interlayerinsulating layer.

The one uneven portion can be formed on a rear surface of the firstsubstrate, and a portion of the first substrate that overlaps the onetransmissive area can include at least one raised rear surface.

The display device can further include a transparent material layerdisposed under the one raised rear surface of the first substrate.

The one uneven portion can be formed on an upper surface of the secondsubstrate, and a portion of the second substrate that overlaps the onetransmissive area can include at least one recessed upper surface or theone hole.

The plurality of insulating layers can include a buffer layer betweenthe substrate and the transistor layer, a planarization layer betweenthe transistor layer and the light emitting device layer, and anencapsulation layer on the light emitting device layer.

The planarization layer can include the one uneven portion at a portionoverlapping the one transmissive area in the first display area.

a concave portion constituting the one uneven portion of theplanarization layer can pass through the insulating layers included inthe transistor layer and the buffer layer positioned under theinsulating layers and can descend to the upper portion of the substrate.

The display panel can further include a plurality of touch sensorsdisposed on the encapsulation layer and a protective layer on theplurality of touch sensors. The protective layer can include at leastone uneven portion at a portion overlapping the one transmissive area.

The plurality of touch sensors can include mesh-type touch sensormetals, and an area of the touch sensor metals per unit area in thefirst display area can be smaller than an area of the touch sensormetals per unit area in the second display area.

The plurality of touch sensors is disposed in the one non-transmissivearea and the plurality of touch sensors is not disposed in the onetransmissive area.

At least one insulating layer including a transmittance improvingstructure can include an organic insulating material.

At least one insulating layer including the transmittance improvingstructure can include a photosensitive material.

The substrate can include a non-photosensitive material.

The shape or size of a concave-convex portion in a portion where thesubstrate overlaps the one transmissive area and the shape or size of aconcave-convex portion in a portion where the one insulating layeroverlaps the one transmissive area can be different from each other.

The number of subpixels per unit area in the first display area is ½ or¼ of the number of subpixels per unit area in the second display area.

The second display area can include a first area, a second area, a thirdarea, and a fourth area. Each of the first area, the second area, thethird area, and the fourth area can be the one non-transmissive area inwhich four subpixels are disposed. The first display area can include afifth area, a sixth area, a seventh area, and an eighth area. Areas ofthe fifth area, the sixth area, the seventh area, and the eighth areacan correspond to areas of the first area, the second area, the thirdarea, and the fourth area. Among the fifth area, the sixth area, theseventh area, and the eighth area, some areas can be the onenon-transmissive area in which four subpixels are disposed, and anotherpartial area can be the one transmissive area in which no subpixels aredisposed.

The light receiving device can include at least one of a camera and aproximity sensor, and the light receiving device may not be exposed onthe front of the display panel.

According to aspects of the present disclosure, a display devicecomprises a display panel including a substrate and a plurality ofinsulating layers, a transistor layer, and a light emitting device layeron the substrate, and including a display area in which an image isdisplayed, the display area including a first display area and a seconddisplay area, and a light receiving device positioned behind the displaypanel and overlapping with the first display area.

The number of subpixels per unit area in the first display area issmaller than the number of subpixels per unit area in the second displayarea,

The first display area includes at least one non-transmissive area inwhich transistors of the transistor layer and light emitting devices ofthe light emitting device layer are located, and at least onetransmissive area through which external light is transmitted to thelight receiving device.

The substrate or at least one insulating layer can have a variablethickness in a portion overlapping the one transmissive area.

According to embodiments of the present disclosure, the display devicein which the light receiving device (e.g., camera, proximity sensor,etc.) is positioned behind the display panel can be provided so that thelight receiving device that should receive light from the front is notexposed to the front.

According to embodiments of the present disclosure, even if the lightreceiving device is positioned behind the display panel, it is possibleto provide the display device in which light from the front surface ofthe display panel can be well transmitted to the light receiving devicethrough the display panel.

According to embodiments of the present disclosure, it is possible toprovide the display device having a higher transmittance in the displaypanel in a region overlapping with the light receiving device comparedto other regions.

According to embodiments of the present disclosure, the display devicein which a transmittance improving structure is formed in a regionoverlapping with the light receiving device in the display panel can beprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the presentdisclosure will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a display device according toembodiments of the present disclosure;

FIGS. 2 and 3 are plan views of a first display area in the displaydevice according to embodiments of the present disclosure;

FIG. 4 is an equivalent circuit for a subpixel in the display deviceaccording to embodiments of the present disclosure;

FIG. 5 is a diagram illustrating a cross-sectional structure of anon-transmissive area in the first display area, a cross-sectionalstructure of a transmissive area in the first display area, and across-sectional structure of a second display area in the display deviceaccording to embodiments of the present disclosure;

FIG. 6 is a cross-sectional view of the display device according toembodiments of the present disclosure;

FIGS. 7A, 7B, and 7C illustrate transmittance improving structures andtheir positions in the display device according to embodiments of thepresent disclosure;

FIG. 8 illustrates a substrate to which a transmittance improvingstructure is applied in the display device according to embodiments ofthe present disclosure;

FIGS. 9A-9D, 10A-10D, and 11A-11B are cross-sectional views illustratingthe substrate to which various transmittance improving structures areapplied in the display device according to embodiments of the presentdisclosure;

FIG. 12 is a cross-sectional view illustrating an insulating layer towhich a transmittance improving structure is applied in the displaydevice according to embodiments of the present disclosure;

FIG. 13 is a diagram for describing structural characteristics of aninsulating layer to which a transmittance improving structure is appliedin the display device according to embodiments of the presentdisclosure;

FIGS. 14 and 15 are cross-sectional views illustrating a case in which atransmittance improving structure is applied in the transmissive area inthe display device according to embodiments of the present disclosure;

FIG. 16 illustrates an arrangement of subpixels in the second displayarea of the display device according to embodiments of the presentdisclosure; and

FIGS. 17A and 17B illustrate an arrangement of subpixels in the firstdisplay area of the display device according to embodiments of thepresent disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the following description of examples or embodiments of the presentdisclosure, reference will be made to the accompanying drawings in whichit is shown by way of illustration specific examples or embodiments thatcan be implemented, and in which the same reference numerals and signscan be used to designate the same or like components even when they areshown in different accompanying drawings from one another. Further, inthe following description of examples or embodiments of the presentdisclosure, detailed descriptions of well-known functions and componentsincorporated herein will be omitted when it is determined that thedescription can make the subject matter in some embodiments of thepresent disclosure rather unclear. The terms such as “including”,“having”, “containing”, “constituting” “make up of”, and “formed of”used herein are generally intended to allow other components to be addedunless the terms are used with the term “only”. As used herein, singularforms are intended to include plural forms unless the context clearlyindicates otherwise.

Terms, such as “first”, “second”, “A”, “B”, “(A)”, or “(B)” can be usedherein to describe elements of the present disclosure. Each of theseterms is not used to define essence, order, sequence, or number ofelements etc., but is used merely to distinguish the correspondingelement from other elements.

When it is mentioned that a first element “is connected or coupled to”,“contacts or overlaps” etc. a second element, it should be interpretedthat, not only can the first element “be directly connected or coupledto” or “directly contact or overlap” the second element, but a thirdelement can also be “interposed” between the first and second elements,or the first and second elements can “be connected or coupled to”,“contact or overlap”, etc. each other via a fourth element. Here, thesecond element can be included in at least one of two or more elementsthat “are connected or coupled to”, “contact or overlap”, etc. eachother.

When time relative terms, such as “after,” “subsequent to,” “next,”“before,” and the like, are used to describe processes or operations ofelements or configurations, or flows or steps in operating, processing,manufacturing methods, these terms can be used to describenon-consecutive or non-sequential processes or operations unless theterm “directly” or “immediately” is used together.

In addition, when any dimensions, relative sizes etc. are mentioned, itshould be considered that numerical values for an elements or features,or corresponding information (e.g., level, range, etc.) include atolerance or error range that can be caused by various factors (e.g.,process factors, internal or external impact, noise, etc.) even when arelevant description is not specified. Further, the term “may” fullyencompasses all the meanings of the term “can”.

FIG. 1 is a schematic diagram of a display device 100 according toembodiments of the present disclosure. All the components of the displaydevice according to all embodiments of the present disclosure areoperatively coupled and configured.

Referring to FIG. 1, the display device 100 according to the embodimentsof the present disclosure can include a display panel 110 displaying animage and a light receiving device 120 receiving light.

The display panel 110 can include a substrate, and a plurality ofinsulating layers, a transistor layer, a light emitting device layer,and the like on the substrate.

The display panel 110 can include a plurality of subpixels fordisplaying an image and various signal lines for driving the pluralityof subpixels. The signal lines can include a plurality of data lines, aplurality of gate lines, and a plurality of power lines. Here, each ofthe plurality of subpixels can include a transistor positioned in thetransistor layer and a light emitting device positioned in the lightemitting device layer.

The display panel 110 can include a display area DA in which an image isdisplayed and a non-display area NDA that is an area outside the displayarea DA. A plurality of subpixels can be disposed in the display areaDA. The various signal lines can be disposed in the non-display areaNDA, and a driving circuit can be connected to the non-display area NDA.The non-display area NDA can be bent and may not be visible from thefront side. The non-display area NDA can be obscured by a case. Thenon-display area NDA can be visible from the front, but an image may notbe displayed. The non-display area NDA is also referred to as a bezel.

Referring to FIG. 1, the display area DA can include a first displayarea DA1 and a second display area DA2.

The light receiving device 120 is a device that receives light andperforms a predetermined function. For example, the light receivingdevice 120 can include one or more cameras and/or one or more proximitysensors.

The light receiving device 120 can be a device requiring lightreception, but can be located behind (below) the display panel 110. Forexample, the light receiving device 120 can be located on the oppositeside of the viewing surface of the display panel 110. The lightreceiving device 120 may not be exposed on the front surface of thedisplay device 100. Therefore, when the user looks at the front of thedisplay device 110, the light receiving device 120 may not be visible byuser.

A camera positioned behind (below) the display panel 110 can be a frontphotographing camera that photographs the front of the display device100. The camera described herein can also be referred to as a cameralens.

Referring to FIG. 1, the light receiving device 120 can be disposed tooverlap the display area DA of the display panel 110. For example, thelight receiving device 120 can be located in the display area DA.

In the display area DA, an area overlapping the light receiving device120 is referred to as the first display area DA1, and the remaining areais referred to as the second display area DA2. Accordingly, the lightreceiving device 120 can be positioned to overlap the first display areaDA1 in the display area DA. In other words, the light receiving device120 can be considered to be located in the first display area DA1 in thedisplay area DA.

Since the first display area DA1 in the display area DA is an areaoverlapping the light receiving device 120, the transmittance of thefirst display area DA1 in the display area DA should be higher than thetransmittance of the second display area DA2 that does not overlap withthe light receiving device 120.

In order to improve the transmittance of the first display area DA1overlapping the light receiving device 120, the resolution, subpixelarrangement structure, number of subpixels per unit area, electrodestructure, wiring structure, electrode arrangement structure, or wiringarrangement structure can be different in the first display area DA1 andthe second display area DA2.

For example, the number of subpixels per unit area in the first displayarea DA1 can be smaller than the number of subpixels per unit area inthe second display area DA2. Accordingly, the resolution of the firstdisplay area DA1 can be lower than that of the second display area DA2.

In the display device 100 according to embodiments of the presentdisclosure, the camera, which is the light receiving device 120 locatedunder the display panel 100 without being exposed to the outside, isalso referred to as an Under Display Camera (UDC).

In the case of the display device 100 according to embodiments, asmaller bezel can be provided, and the notch-shaped display panel 110may not be manufactured. In addition, design restrictions due to thelight receiving device 120 can be reduced or eliminated, so that adegree of freedom in design can be increased.

In the display device 100 according to embodiments of the presentdisclosure, although the light receiving device 120 is positioned behindthe display panel 110, the light receiving device 120 can normallyreceive light and perform a predetermined function normally. Inaddition, in the display device 100 according to embodiments of thepresent disclosure, although the light receiving device 120 ispositioned behind the display panel 110 and overlapped with the displayarea DA, the light receiving device 120 can normally receive lightthrough the display area DA. Accordingly, the predetermined functionthrough light reception can be normally performed. In the display device100 according to embodiments of the present disclosure, although thelight receiving device 120 is positioned behind the display panel 110and overlapped with the display area DA, the display device 100 canperform normal image display in the display area DA.

Accordingly, the display device 100 according to embodiments of thepresent disclosure provides a structure capable of improving thetransmittance of the first display area DA1 overlapping the lightreceiving device 120.

FIGS. 2 and 3 are plan views of the first display area DA1 in thedisplay device 100 according to embodiments of the present disclosure.

FIG. 3 illustrates the first display area DA1 in which signal lines SLand emission areas EA1, EA2, EA3, and EA4 of subpixels are additionallydisplayed compared to FIG. 2.

Referring to FIGS. 2 and 3, the first display area DA1 can be an areaoverlapping the light receiving device 120. The first display area DA1can include at least one non-transmissive area NTA and at least onetransmissive area TA.

Referring to FIGS. 2 and 3, the at least one transmissive area TA can beat least one partial area included in the first display area DA1 and canbe at least one area through which external light is transmitted to thelight receiving device 120. For example, each transmissive area TA canhave a circular or elliptical shape, and can also be referred to as ahole area.

Referring to FIGS. 2 and 3, the at least one non-transmissive area NTAcan be at least one partial area included in the first display area DA1.The at least one non-transmissive area NTA can be at least one area inwhich the transistors of the transistor layer and the light emittingdevices of the light emitting device layer are located.

Referring to FIGS. 2 and 3, the at least one non-transmissive area NTAcan include a pixel area PA in which the emission areas EA1, EA2, EA3,and EA4 of the subpixels exist, and a signal line area SLA in which thesignal lines SL are disposed.

Referring to FIGS. 2 and 3, when each transmissive area TA is surroundedby the at least one non-transmissive area NTA, the first display areaDA1 can include a plurality of transmissive areas TA separated from eachother.

FIG. 4 is an equivalent circuit for a subpixel SP in the display device100 according to embodiments of the present disclosure.

Referring to FIG. 4, each or at least one of the plurality of subpixelsSP disposed on the display panel 110 of the display device 100 accordingto embodiments of the present disclosure can include a light emittingdevice ED, a driving transistor DRT, a scan transistor SCT, a storagecapacitor Cst, and the like.

The light emitting device ED can include a pixel electrode PE and acommon electrode CE, and a light emitting layer EL positioned betweenthe pixel electrode PE and the common electrode CE. Here, the pixelelectrode PE can be disposed in each subpixel SP, and the commonelectrode CE can be disposed in common with a plurality of subpixels SP.For example, the pixel electrode PE can be an anode electrode, and thecommon electrode CE can be a cathode electrode. For another example, thepixel electrode PE can be a cathode electrode, and the common electrodeCE can be an anode electrode. For example, the light emitting device EDcan be an organic light emitting diode (OLED), an inorganic lightemitting diode (ILED), or a quantum dot light emitting device. Theinorganic light emitting diode (ILED) can be a micro light emittingdiode.

The driving transistor DRT can be a transistor for driving the lightemitting device ED, and can include a first node N1, a second node N2, athird node N3, and the like.

The first node N1 of the driving transistor DRT can be a gate node ofthe driving transistor DRT, and can be electrically connected to asource node or a drain node of the scan transistor SCT. The second nodeN2 of the driving transistor DRT can be a source node or a drain node ofthe driving transistor DRT, and can be electrically connected to thepixel electrode PE of the light emitting device ED. The third node N3 ofthe driving transistor DRT can be electrically connected to the drivingvoltage line DVL supplying the driving voltage EVDD.

The scan transistor SCT can be controlled by the scan signal SCAN andcan be connected between the first node N1 of the driving transistor DRTand the data line DL. The scan transistor SCT can be turned on or offaccording to the scan signal SCAN supplied from the gate line GL.Accordingly, the scan transistor SCT can control a connection betweenthe data line DL and the first node N1 of the driving transistor DRT.

The scan transistor SCT can be turned on by a scan signal SCAN having aturn-on level voltage. Accordingly, the scan transistor SCT can transmitthe data voltage Vdata supplied from the data line DL to the first nodeN1 of the driving transistor DRT.

The turn-on level voltage of the scan signal SCAN capable of turning onthe scan transistor SCT can be a high level voltage or a low levelvoltage. The turn-off level voltage of the scan signal SCAN capable ofturning off the scan transistor SCT can be a low level voltage or a highlevel voltage. For example, when the scan transistor SCT is an n-typetransistor, the turn-on level voltage can be a high level voltage andthe turn-off level voltage can be a low level voltage. For anotherexample, when the scan transistor SCT is a p-type transistor, theturn-on level voltage can be a low level voltage and the turn-off levelvoltage can be a high level voltage.

Each of the driving transistor DRT and the scan transistor SCT can be ann-type transistor or a p-type transistor.

The storage capacitor Cst can be connected between the first node N1 andthe second node N2 of the driving transistor DRT. The storage capacitorCst can charge the amount of charge corresponding to the voltagedifference between both ends and can maintain the voltage differencebetween both ends for a predetermined frame time. Accordingly, during apredetermined frame time, the subpixel SP can emit light.

The storage capacitor Cst may not be a parasitic capacitor (e.g., Cgs,Cgd), which is an internal capacitor existing between a gate node and asource node (or drain node) of the driving transistor DRT, but can be anexternal capacitor intentionally designed outside the driving transistorDRT.

The subpixel SP of the display device 100 according to embodiments canfurther include one or more transistors and/or can further include oneor more capacitors.

FIG. 5 is a diagram illustrating a cross-sectional structure of thenon-transmissive area NTA in the first display area DA1, across-sectional structure of the transmissive area TA in the firstdisplay area DA1, and a cross-sectional structure of the second displayarea DA2 in the display device 100 according to embodiments of thepresent disclosure.

Referring to FIG. 5, the first display area DA1 of the display panel 110can include at least one transmissive area TA and at least onenon-transmissive area NTA. The second display area DA2 of the displaypanel 110 can be viewed as a non-transmissive area NTA.

Referring to FIG. 5, a stacked structure of at least onenon-transmissive area NTA in the first display area DA1, a stackedstructure of at least one transmissive area TA in the first display areaDA1, and a stacked structure of the second display area DA2 will bedescribed below.

Referring to FIG. 5, the stacked structure of the second display areaDA2 is as follows.

In the second display area DA2, a transistor layer TRL can be disposedon the substrate SUB, a planarization layer PLN can be disposed on thetransistor layer TRL, a light emitting device layer EDL can be disposedon the planarization layer PLN, an encapsulation layer ENCAP can bedisposed on the light emitting device layer EDL, a touch sensor layerTSL can be disposed on the encapsulation layer ENCAP, and a protectivelayer PAC can be disposed on the touch sensor layer TSL.

In the second display area DA2, transistors such as the drivingtransistor DRT and the scan transistor SCT of each subpixel SP can bedisposed in the transistor layer TRL, and various insulating layers forforming transistors can be further disposed in the transistor layer TRL.Here, various insulating layers can include at least one organic layerand/or at least one inorganic layer.

In the second display area DA2, various signal lines, such as data linesDL, gate lines GL, and driving voltage lines DVL, can be disposed in thetransistor layer TRL.

In the second display area DA2, the light emitting device ED of eachsubpixel SP can be disposed in the light emitting device layer EDL.Accordingly, in the light emitting device layer EDL in the seconddisplay area DA2, the pixel electrode PE, the light emitting layer EL,and the common electrode CE constituting the light emitting device EDcan be disposed.

In the second display area DA2, a plurality of touch sensors TS can bedisposed on the touch sensor layer TSL. In addition, in the seconddisplay area DA2, a touch buffer layer and a touch insulating layerrequired to form a plurality of touch sensors TS can be further disposedon the touch sensor layer TSL.

Referring to FIG. 5, the stacked structure of at least onenon-transmissive area NTA in the first display area DA1 can be the sameas that of the second display area DA2.

In the non-transmissive area NTA in the first display area DA1, atransistor layer TRL can be disposed on the substrate SUB, aplanarization layer PLN can be disposed on the transistor layer TRL, alight emitting device layer EDL can be disposed on the planarizationlayer PLN, an encapsulation layer ENCAP can be disposed on the lightemitting device layer EDL, a touch sensor layer TSL can be disposed onthe encapsulation layer ENCAP, and a protective layer PAC can bedisposed on the touch sensor layer TSL.

The light emitting device ED can be vulnerable to moisture or oxygen.The encapsulation layer ENCAP can prevent penetration of moisture oroxygen, thereby preventing the light emitting device ED from beingexposed to moisture or oxygen. The encapsulation layer ENCAP can be asingle layer. Alternatively, the encapsulation layer ENCAP can includemultiple layers.

In the non-transmissive area NTA in the first display area DA1,transistors such as the driving transistor DRT and the scan transistorSCT of each subpixel SP can be disposed in the transistor layer TRL.Various insulating layers for forming transistors can be furtherdisposed in the transistor layer TRL. Here, various insulating layerscan include at least one organic layer and/or at least one inorganiclayer.

In the non-transmissive area NTA in the first display area DA1, varioussignal lines, such as data lines DL, gate lines GL, and driving voltagelines DVL, can be disposed in the transistor layer TRL.

In the non-transmissive area NTA in the first display area DA1, thelight emitting device ED of each subpixel SP can be disposed in thelight emitting device layer EDL. Accordingly, in the light emittingdevice layer EDL in the first display area DA1, the pixel electrode PE,the emission layer EL, and the common electrode CE constituting thelight emitting device ED can be disposed.

In the non-transmissive area NTA in the first display area DA1, aplurality of touch sensors TS can be disposed in the touch sensor layerTSL. In addition, in the non-transmissive area NTA in the first displayarea DA1, a touch buffer layer and a touch insulating layer required toform a plurality of touch sensors TS can be further disposed.

Referring to FIG. 5, the stacked structure of the transmissive area TAin the first display area DA1 can be as follows.

Referring to FIG. 5, in the transmissive area TA in the first displayarea DA1, a transistor layer TRL can be disposed on the substrate SUB, aplanarization layer PLN can be disposed on the transistor layer TRL, alight emitting device layer EDL can be disposed on the planarizationlayer PLN, an encapsulation layer ENCAP can be disposed on the lightemitting device layer EDL, a touch sensor layer TSL can be disposed onthe encapsulation layer ENCAP, and a protective layer PAC can bedisposed on the touch sensor layer TSL.

In the transmissive area TA in the first display area DA1, transistorssuch as the driving transistor DRT and the scan transistor SCT of eachsubpixel SP and various signal lines can be disposed in the transistorlayer TRL. In the transmissive area TA in the first display area DA1,the light emitting device ED of each subpixel SP can be disposed in thelight emitting device layer EDL. In the transmissive area TA in thefirst display area DA1, a plurality of touch sensors TS can be disposedon the touch sensor layer TSL.

Alternatively, transistors and signal lines may not be disposed in thetransistor layer TRL in the at least one transmissive area TA in thefirst display area DA1. However, in the transmissive area TA in thefirst display area DA1, various insulating layers can be disposed in thetransistor layer TRL. Here, various insulating layers can include atleast one organic layer and/or at least one inorganic layer.

In the transmissive area TA in the first display area DA1, the lightemitting device ED of each subpixel SP may not be disposed in the lightemitting device layer EDL. Accordingly, in the transmissive area TA inthe first display area DA1, the pixel electrode PE, the emission layerEL, and the common electrode CE may not be disposed in the lightemitting device layer EDL. In some cases, in the transmissive area TA inthe first display area DA1, only a part of the pixel electrode PE, theemission layer EL, and the common electrode CE can be disposed in thelight emitting device layer EDL. For example, in the transmissive areaTA in the first display area DA1, only the emission layer EL can bedisposed in the light emitting device layer EDL.

In the transmissive area TA in the first display area DA1, a pluralityof touch sensors TS may not be disposed in the touch sensor layer TSL.However, in the transmissive area TA in the first display area DA1, atouch buffer layer and a touch insulating layer can be disposed on thetouch sensor layer TSL.

Referring to FIG. 5, among a metal material layer and an insulatingmaterial layer disposed in the non-transmissive area NTA of the firstdisplay area DA1 and the non-transmissive area NTA of the second displayarea DA2, the metal material layer may not be disposed in thetransmissive area TA in the first display area DA1. However, among themetal material layer and the insulating material layer disposed in thenon-transmissive area NTA of the first display area DA1 and thenon-transmissive area NTA of the second display area DA2, the insulatingmaterial layer can be disposed to extend to the transmissive area TA inthe first display area DA1.

In other words, the metal material layer can be disposed in thenon-transmissive area NTA of the first display area DA1 and thenon-transmissive area NTA of the second display area DA2. However, themetal material layer may not be disposed in the transmissive area TA inthe first display area DA1. The insulating material layer can becommonly disposed in the non-transmissive area NTA of the first displayarea DA1, the non-transmissive area NTA of the second display area DA2,and the transmissive area TA of the first display area DA1.

Referring to FIG. 5, the at least one transmissive area TA in the firstdisplay area DA1 of the display panel 110 can overlap the lightreceiving device 120.

External light can be transmitted to the light receiving device 120through the at least one transmissive area TA in the first display areaDA1. Accordingly, in order for the light receiving device 120 to operatenormally, the transmittance of the at least one transmissive area TA inthe first display area DA1 must be high.

FIG. 6 is a cross-sectional view of the display device 100 according toembodiments of the present disclosure. FIG. 6 is an example of across-sectional structure of the non-transmissive area NTA and thetransmissive area TA in the first display area DA1.

Referring to FIG. 6, both the non-transmissive area NTA and thetransmissive area TA included in the first display area DA1 canbasically include the substrate SUB, the transistor layer TRL, theplanarization layer PLN, the light emitting device layer EDL, theencapsulation layer ENCAP, the touch sensor layer TSL, and theprotective layer PAC.

First, with reference to FIG. 6, a stacked structure of thenon-transmissive area NTA included in the first display area DA1 will bedescribed below.

The substrate SUB can include a first substrate SUB1, an interlayerinsulating layer IPD, and a second substrate SUB2. The interlayerinsulating layer IPD can be positioned between the first substrate SUB1and the second substrate SUB2. By configuring the substrate SUB with thefirst substrate SUB1, the interlayer insulating layer IPD, and thesecond substrate SUB2, moisture penetration can be prevented. Forexample, the first substrate SUB1 and the second substrate SUB2 can bepolyimide (PI) substrates.

The transistor layer TRL can include various patterns ACT, SD1, and GATEfor forming a transistor (e.g., driving transistor DRT, scan transistorSCT, etc.), various insulating layers MBUF, ABUF1, ABUF2, GI, ILD1,ILD2, and PAS0, and various metal patterns TM, GM, ML1 and ML2. In FIG.6, the driving transistor DRT formed on the transistor layer TRL isillustrated as an example.

In the following, the stacked structure of the transistor layer TRL isdescribed in more detail.

A multi-buffer layer MBUF can be disposed on the second substrate SUB2,and a first active buffer layer ABUF1 can be disposed on themulti-buffer layer MBUF.

A first metal layer ML1 and a second metal layer ML2 can be disposed onthe first active buffer layer ABUF1. Here, the first metal layer ML1 andthe second metal layer ML2 can serve as a light shield.

A second active buffer layer ABUF2 can be disposed on the first metallayer ML1 and the second metal layer ML2. An active layer ACT of thedriving transistor DRT can be disposed on the second active buffer layerABUF2.

A gate insulating layer GI can be disposed to cover the active layerACT.

A gate electrode GATE of the driving transistor DRT can be disposed onthe gate insulating layer GI. In this case, a gate material layer GM canbe disposed on the gate insulating layer GI together with the gateelectrode GATE of the driving transistor DRT at a position differentfrom the formation position of the driving transistor DRT.

A first interlayer insulating layer ILD1 can be disposed while coveringthe gate electrode GATE and the gate material layer GM. A metal patternTM can be disposed on the first interlayer insulating layer ILD1. Thesecond interlayer insulating layer ILD2 can be disposed while coveringthe metal pattern TM on the first interlayer insulating layer ILD1.

Two first source-drain electrode patterns SD1 can be disposed on thesecond interlayer insulating layer ILD2. One of the two firstsource-drain electrode patterns SD1 can be a source node of the drivingtransistor DRT, and the other can be a drain node of the drivingtransistor DRT.

The two first source-drain electrode patterns SD1 can be connected toone side and the other side of the active layer ACT through contactholes of the second interlayer insulating layer ILD2, the firstinterlayer insulating layer ILD1, and the gate insulating layer GI. Aportion of the active layer ACT overlapping the gate electrode GATE canbe a channel region. Of the two first source-drain electrode patternsSD1, one can be connected to one side (first non-channel region) of thechannel region in the active layer ACT, and the other can be connectedto the other side (second non-channel region) of the channel region inthe active layer ACT.

The passivation layer PAS0 can be disposed while covering the two firstsource-drain electrode patterns SD1.

A planarization layer PLN can be disposed on the transistor layer TRL.The planarization layer PLN can include a first planarization layer PLN1and a second planarization layer PLN2.

The first planarization layer PLN1 can be disposed on the passivationlayer PAS0. A second source-drain electrode pattern SD2 can be disposedon the first planarization layer PLN1. The second source-drain electrodepattern SD2 can be connected to one (electrically corresponding to theN2 node in FIG. 4) of the two first source-drain electrode patterns SD1through a contact hole of the first planarization layer PLN1.

The second planarization layer PLN2 can be disposed while covering thesecond source-drain electrode pattern SD2. The light emitting devicelayer EDL can be positioned on the second planarization layer PLN2.

The lamination structure of the light emitting device layer EDL will bedescribed below.

The pixel electrode PE can be disposed on the second planarization layerPLN2. The pixel electrode PE can be electrically connected to the secondsource-drain electrode pattern SD2 through a contact hole of the secondplanarization layer PLN2.

The bank BANK can be disposed while covering a portion of the pixelelectrode PE. The bank can open a portion corresponding to the emissionarea of the subpixel SP. A portion of the pixel electrode PE can beexposed as a portion in which the bank BANK is open. The light-emittinglayer EL can be disposed on and around the open portion of the bank.Accordingly, the emission layer EL can be disposed on the pixelelectrode PE exposed through the open portion of the bank.

A common electrode CE can be disposed on the emission layer EL. Forexample, the common electrode CE can be a cathode electrode.

The light emitting device ED can be formed by the pixel electrode PE,the light emitting layer EL, and the common electrode CE. The emissionlayer EL can include an organic layer.

An encapsulation layer ENCAP can be disposed on the light emittingdevice layer EDL described above.

The encapsulation layer (ENCAP) can have a single-layer structure or amulti-layer structure. For example, as shown in FIG. 6, theencapsulation layer ENCAP can include a first encapsulation layer PAS1,a second encapsulation layer PCL, and a third encapsulation layer PAS2.

The first encapsulation layer PAS1 and the third encapsulation layerPAS2 can be an inorganic layer, and the second encapsulation layer PCLcan be an organic layer. Among the first encapsulation layer PAS1, thesecond encapsulation layer PCL, and the third encapsulation layer PAS2,the second encapsulation layer PCL can be the thickest and can serve asa planarization layer.

The first encapsulation layer PAS1 can be disposed on the commonelectrode CE, and can be disposed closest to the light emitting deviceED. The first encapsulation layer PAS1 can be formed of an inorganicinsulating material capable of low-temperature deposition. For example,the first encapsulation layer PAS1 can include silicon nitride (SiNx),silicon oxide (SiOx), silicon oxynitride (SiON), or aluminum oxide(Al₂O₃). Since the first encapsulation layer PAS1 is deposited in a lowtemperature atmosphere, during the deposition process, the firstencapsulation layer PAS1 can prevent damage to the light emitting layerEL including an organic material vulnerable to the high temperatureatmosphere.

The second encapsulation layer PCL can be formed to have a smaller areathan the first encapsulation layer PAS1. In this case, the secondencapsulation layer PCL can be formed to expose both ends of the firstencapsulation layer PAS1. The second encapsulation layer PCL can serveas a buffer to relieve stress between layers due to bending of thedisplay device 100 and can also serve to enhance planarizationperformance. For example, the second encapsulation layer PCL can includeacrylic resin, epoxy resin, polyimide, polyethylene, or siliconoxycarbon (SiOC), and can include an organic insulating material. Forexample, the second encapsulation layer PCL can be formed through aninkjet method.

For reference, in the display panel 110, in order to prevent theencapsulation layer ENCAP from collapsing, one or more dams can exist ator near the end of the inclined surface of the encapsulation layerENCAP. One or more dams can exist at a boundary point between thedisplay area DA and the non-display area NDA, or can exist in thevicinity of the boundary point.

The second encapsulation layer PCL including organic matter can belocated only on the inner side of the innermost first dam among thefirst dam and the second dam. In this case, the second encapsulationlayer PCL may not exist on top of all dams. Alternatively, the secondencapsulation layer PCL including an organic material can be positionedabove at least the first dam among the first dam and the second dam. Forexample, the second encapsulation layer PCL can be extended andpositioned only to the upper part of the first dam. Alternatively, thesecond encapsulation layer PCL can be positioned to extend to the upperpart of the second dam through the upper part of the first dam.

The third encapsulation layer PAS2 can be disposed on the substrate SUBon which the second encapsulation layer PCL is formed, and be arrangedto cover the upper and side surfaces of the second encapsulation layerPCL and the first encapsulation layer PAS1 respectively. The thirdencapsulation layer PAS2 can minimize or block external moisture oroxygen from penetrating into the first encapsulation layer PAS1 and thesecond encapsulation layer PCL. For example, the third encapsulationlayer PAS2 can include an inorganic insulating material such as siliconnitride (SiNx), silicon oxide (SiOx), silicon oxynitride (SiON), oraluminum oxide (Al₂O₃).

The touch sensor layer TSL can be disposed on the above-describedencapsulation layer ENCAP. Hereinafter, a stacked structure of the touchsensor layer TSL will be described.

The touch buffer layer T-BUF can be disposed on the encapsulation layerENCAP, and the touch sensor TS can be disposed on the touch buffer layerT-BUF. The touch sensor TS can include touch sensor metals TSM andbridge metal BRG positioned on different layers. A touch interlayerinsulating layer T-ILD can be disposed between the touch sensor metalsTSM and the bridge metal BRG.

For example, the touch sensor metals TSM can include a first touchsensor metal TSM, a second touch sensor metal TSM, and a third touchsensor metal TSM disposed adjacent to each other. When the first touchsensor metal TSM and the second touch sensor metal TSM are electricallyconnected to each other and the third touch sensor metal TSM is disposedbetween the first touch sensor metal TSM and the second touch sensormetal TSM, the first touch sensor metal TSM and the second touch sensormetal TSM can be electrically connected through a bridge metal BRGpositioned on a different layer from the first touch sensor metal TSMand the second touch sensor metal TSM. The bridge metal BRG can beinsulated from the third touch sensor metal TSM by the touch interlayerinsulating layer T-ILD.

When the touch sensor layer TSL is formed, a chemical solution(developer or etchant, etc.) used in a process or moisture from theoutside can be generated. By disposing the touch buffer layer T-BUF anddisposing the touch sensor layer TSL thereon, it is possible to preventa chemical solution or moisture from penetrating into the light emittinglayer EL containing an organic material during the manufacturing processof the touch sensor layer TSL. Accordingly, the touch buffer layer T-BUFcan prevent damage to the light emitting layer EL vulnerable tochemicals or moisture.

In order to prevent damage to the light-emitting layer EL containingorganic substances susceptible to high temperatures, the touch bufferlayer T-BUF can include an organic insulating material that can beformed at a low temperature below a certain temperature (e.g., 100° C.).Here, the organic insulating materials can have a low dielectricconstant of 1 to 3. For example, the touch buffer layer T-BUF can beformed of an acrylic-based, epoxy-based, or siloxan-based material. Asthe display device 100 is bent, the encapsulation layer ENCAP can bedamaged, and the touch sensor metal TSM and BRG positioned on the touchbuffer layer T-BUF can be broken. Since the touch buffer layer T-BUF ismade of an organic insulating material and has a planarizationperformance, the touch buffer layer T-BUF can prevent damage to theencapsulation layer ENCAP or cracking of the touch sensor metal TSM andBRG even if the display device 100 is bent.

The protective layer PAC can be disposed while covering the touch sensorTS. The protective layer PAC can be an organic insulating layer.

Hereinafter, the stacked structure of the transmissive area TA in thefirst display area DA1 will be described with reference to FIG. 6.

Referring to FIG. 6, the substrate SUB and the insulating layers (MBUF,ABUF1, ABUF2, GI, ILD1, ILD2, PAS0, PLN(PLN1, PLN2), BANK, ENCAP(PAS1,PCL, PAS2), PAC) disposed in the non-transmissive area NTA in the firstdisplay area DA1 can be equally disposed in the transmissive area TA inthe first display area DA1.

The insulating material included in the insulating layers can bedisposed in the non-transmissive area NTA in the first display area DA1,and can also be disposed in the transmissive area TA in the firstdisplay area DA1. However, the material layer (e.g., metal materiallayer, semiconductor layer, etc.) having electrical characteristics isdisposed in the non-transmissive area NTA in the first display area DA1,but may not be disposed in the transmissive area TA in the first displayarea DA1.

For example, the metal material layers ML1, ML2, GATE, GM, TM, SD1, andSD2 related to the transistor and the active layer ACT may not bedisposed in the transmissive area TA. The pixel electrode PE and thecommon electrode CE included in the light emitting device ED may not bedisposed in the transmissive area TA. The emission layer EL may or maynot be disposed in the transmissive area TA. The touch sensor metal TSMand the bridge metal BRG included in the touch sensor TS may not bedisposed in the transmissive area TA.

Since the transmissive area TA in the first display area DA1 of thedisplay panel 110 overlaps with the light receiving device 120, thetransmittance of the transmissive area TA in the first display area DA1needs to be high for normal operation of the light receiving device 120.

To this end, in the display panel 110 of the display device 100according to embodiments of the present disclosure, the transmissivearea TA in the first display area DA1 can have a transmittance improvingstructure TIS. Hereinafter, the transmittance improving structure TISwill be described in detail.

FIGS. 7A, 7B, and 7C illustrate transmittance improving structures TISand their positions in the display device 100 according to embodimentsof the present disclosure.

Referring to FIGS. 7A, 7B and 7C, in the display device 100 according tothe embodiments of the present disclosure, the substrate SUB or at leastone insulating layer (e.g., PLN, PAC, etc.) among the plurality ofinsulating layers (MBUF, ABUF1, ABUF2, GI, ILD1, ILD2, PAS0, PLN1, PLN2,BANK, PAS1, PCL, PAS2, PAC) can have a transmittance improving structureTIS in a portion overlapping the transmissive area TA in the firstdisplay area DA1.

Here, the transmittance improving structure TIS can include at least onehole or at least one uneven portion (also called stepped portion).

As described above, in the display device 100 according to theembodiments of the present disclosure, the substrate SUB or at least oneinsulating layer (e.g., PLN, PAC, etc.) among the plurality ofinsulating layers (MBUF, ABUF1, ABUF2, GI, ILD1, ILD2, PAS0, PLN1, PLN2,BANK, PAS1, PCL, PAS2, PAC) can have a variable thickness in a portionoverlapping the transmissive area TA.

Referring to FIG. 7A, the substrate SUB can include at least one hole orat least one uneven portion as a transmittance improving structure TISin a portion overlapping the transmissive area TA.

When a hole is formed in a portion of the substrate SUB that overlapsthe transmissive area TA, the transmittance of the substrate SUB can besignificantly improved.

When the uneven portion is formed in a portion of the substrate SUB thatoverlaps the transmissive area TA, the uneven portion can serve as acondensing lens. Accordingly, light descending from the upper portion ofthe substrate SUB can be condensed by the uneven portion. Due to this,more light can be transmitted to the light receiving device 120.Accordingly, the transmittance of the substrate SUB can be significantlyimproved.

Referring to FIG. 7B, among a plurality of insulating layers, theplanarization layer PLN can be disposed between the transistor layer TRLand the light emitting device layer EDL. The planarization layer PLN canhave at least one uneven portion (also referred to as a step portion) asa transmittance improving structure TIS in a portion overlapping thetransmissive area TA.

When an uneven portion is formed in a portion of the planarization layerPLN that overlaps the transmissive area TA, the uneven portion can serveas a condensing lens. Accordingly, light descending from the top of theplanarization layer PLN can be condensed by the uneven portion, andthus, more light can be transmitted to the light receiving device 120.Accordingly, the transmittance of the planarization layer PLN can besignificantly improved.

Referring to FIG. 7C, a protective layer PAC among a plurality ofinsulating layers can be disposed on the touch sensor layer TSL. Theprotective layer PAC can have at least one uneven portion (also referredto as a step portion) as the transmittance improving structure TIS in aportion overlapping the transmissive area TA.

When an uneven portion is formed in a portion of the protective layerPAC that overlaps the transmissive area TA, the uneven portion can serveas a condensing lens. Accordingly, light descending from the upper partof the protective layer PAC can be condensed by the uneven portion, andthus, more light can be transmitted to the light receiving device 120.Accordingly, the transmittance of the protective layer PAC can besignificantly improved.

Referring to FIGS. 7B and 7C, at least one insulating layer PLN and PACas the transmittance improving structure TIS can include an organicinsulating material.

Referring to FIGS. 7A, 7B, and 7C, at least one insulating layer PLN andPAC serving as the transmittance improving structure TIS can include aphotosensitive material. In contrast, the substrate SUB can include anon-photosensitive material.

Referring to FIGS. 7A, 7B and 7C, the shape or size of the unevenportion of the portion where the substrate SUB overlaps the transmissivearea TA and the shape or size of the uneven portion of the portion wherethe at least one insulating layer PLN and PAC overlap the transmissivearea TA can be different from each other. For example, the shape of theuneven portion of the portion where the substrate SUB overlaps thetransmissive area TA and the shape of the uneven portion of the portionwhere the at least one insulating layer PLN and PAC overlap thetransmissive area TA can be different from each other. Alternatively,the size (e.g., width, depth, etc.) of the uneven portion in the portionwhere the substrate SUB overlaps the transmissive area TA and the size(e.g., width, depth (thickness), etc.) of the uneven portion in theportion where the at least one insulating film PLN and PAC overlaps thetransmissive area TA can be different from each other.

FIG. 8 illustrates the substrate SUB to which a transmittance improvingstructure TIS is applied in the display device 100 according toembodiments of the present disclosure. FIGS. 9A to 11B arecross-sectional views illustrating the substrate SUB to which varioustransmittance improving structures TIS are applied in the display device100 according to embodiments of the present disclosure. FIGS. 9A to 11Bare cross-sectional views taken along the line A-B of FIG. 8.

Referring to FIG. 8, the substrate SUB can have a plurality oftransmittance improving structures TIS in a portion overlapping thetransmissive area TA in the first display area DA1.

Referring to FIG. 9A, a hole can be formed in a portion of the substrateSUB that overlaps the transmissive area TA. Accordingly, thetransmittance of the substrate SUB can be improved. It is assumed thatthe original thickness of the substrate SUB is T1.

Referring to FIG. 9B, a portion of the substrate SUB that overlaps thetransmissive area TA can include at least one raised rear surface,thereby forming at least one uneven portion on the rear surface of thesubstrate SUB. Accordingly, the substrate thickness T2 of the portionwhere the rear surface is raised can be thinner than the substratethickness T1 of the portion where the rear surface is not raised.

Referring to FIG. 9C, a transparent material layer TML can be disposedunder the rear surface raised from the substrate SUB. Here, for example,the transparent material layer TML can include SiO₂. The thickness ofthe transparent material layer TML can correspond to a height at whichthe rear surface of the substrate SUB is raised.

Referring to FIG. 9D, a portion of the substrate SUB that overlaps thetransmissive area TA can include at least one recessed upper surface, sothat at least one uneven portion can be formed on the upper surface ofthe substrate SUB. Accordingly, the substrate thickness T2 of theportion in which the upper surface is depressed can be thinner than thesubstrate thickness T1 of the portion in which the upper surface is notdepressed.

Referring to FIGS. 10A-10D and 11A-11B, the substrate SUB can include afirst substrate SUB1, an interlayer insulating layer IPD on the firstsubstrate SUB1, and a second substrate SUB2 on the interlayer insulatinglayer IPD. Since the substrate SUB has a multi-layered structure,penetration of moisture under the substrate SUB can be prevented.

Referring to FIGS. 10A to 10D, a portion of the first substrate SUB1overlapping the transmissive area TA can include at least one raisedrear surface. At least one uneven portion can be formed on the rearsurface of the first substrate SUB1. Accordingly, the substratethickness T2 of the portion where the rear surface is raised can bethinner than the substrate thickness T1 of the portion where the rearsurface is not raised.

Referring to FIGS. 10A to 10D, when the display panel 110 ismanufactured, the substrate SUB can be formed on the glass.

During the manufacturing process of the display panel 110, the glass canbe removed through a laser lift off (LLO) process.

In addition, a sacrificial layer SACL can be formed on the glass, and asubstrate SUB can be formed thereon. The sacrificial layer SACL can beremoved together with glass during the LLO process. By using thesacrificial layer SACL, it is possible to prevent damage to theinterlayer insulating layer IPD during the LLO process.

Referring to FIGS. 10A and 10B, the first substrate SUB1 can be formedon glass in which a portion is etched. Accordingly, at least one rearsurface can be raised in a portion of the first substrate SUB1 thatoverlaps the transmissive area TA. The rear surface raised from thefirst substrate SUB1 can correspond to a portion of the glass that isnot etched.

Referring to FIGS. 10A and 10B, the elevation heights Ha and Hb of therear surface of the first substrate SUB1 can vary according to thedegree or the height of etching of the glass.

Referring to FIGS. 10C and 10D, a transparent material layer TML can bedisposed under the raised rear surface of the first substrate SUB1.Here, for example, the transparent material layer TML can include SiO₂.The thicknesses Ha and Hb of the transparent material layer TML cancorrespond to heights Ha and Hb at which the rear surface of the firstsubstrate SUB1 is raised.

Referring to FIGS. 10C and 10D, in the manufacturing process of thedisplay panel 110, a transparent material layer TML can be formed at adesired height Ha and Hb at specific points on the glass. Thereafter, asubstrate SUB can be formed. In this case, the rear surface of the firstsubstrate SUB1 can be raised to a desired height (Ha, Hb).

Referring to FIGS. 11A and 11B, after the substrate SUB is formed, thesubstrate SUB can be etched to form an uneven portion.

Referring to FIG. 11A, when the etching depth Da of the substrate SUB issmaller than the thickness of the second substrate SUB2, a portion ofthe second substrate SUB2 that overlaps the transmissive area TA caninclude a recessed upper surface. Accordingly, at least one unevenportion can be formed on the upper surface of the second substrate SUB2.Accordingly, the substrate thickness T2 of the portion in which theupper surface is depressed can be thinner than the substrate thicknessT1 of the portion in which the upper surface is not depressed.

Referring to FIG. 11B, when the etching depth Db of the substrate SUB isgreater than the thickness of the second substrate SUB2, a portion ofthe substrate SUB that overlaps the transmissive area TA can include arecessed upper surface. Accordingly, at least one uneven portion can beformed on the upper surface of the substrate SUB. Accordingly, thesubstrate thickness T2 of the portion in which the upper surface isdepressed can be thinner than the substrate thickness T1 of the portionin which the upper surface is not depressed.

Referring to FIG. 11B, when the etching depth Db of the substrate SUB isgreater than the thickness of the second substrate SUB2, at least onegroove having a predetermined depth Db can be formed in a portion of thesubstrate SUB that overlaps the transmissive area TA. For example, theat least one groove can include a hole in the second substrate SUB2, ahole in the interlayer insulating layer IPD, and a groove in the firstsubstrate SUB1. For another example, the at least one groove can beformed of a hole of the second substrate SUB2 and a groove of theinterlayer insulating layer IPD.

FIG. 12 is a cross-sectional view illustrating an insulating layer INSto which a transmittance improving structure TIS is applied in thedisplay device 100 according to embodiments of the present disclosure.FIG. 13 is a diagram for describing structural characteristics of aninsulating layer INS to which a transmittance improving structure TIS isapplied in the display device 100 according to embodiments of thepresent disclosure.

Referring to FIG. 12, as described above, at least one insulating layerINS of the plurality of insulating layers formed on the display panel110 can have a transmittance improving structure TIS in a portionoverlapping the transmissive area TA in the first display area DA1.

For example, the transmittance improving structure TIS can include atleast one uneven portion (also referred to as a step portion).

Referring to FIG. 12, the uneven portion can include a plurality ofridges M.

The ridge M can be defined by a height H, a base length D, a slope S,and the like. The higher the height H, the higher the ridge M can be.And, as the base length D increases, the area of the ridge M canincrease. As the slope S increases, the slope of the ridge M becomessteeper and the shape of the ridge M becomes sharper.

Referring to FIG. 12, the shape of the uneven portion of the insulatinglayer INS can change according to the distance G between two adjacentridges M. At a certain intermediate height (e.g., ½H) of the ridge M,the middle width F of the ridge M can indicate how sharp the ridge M is.

In order to reduce diffuse reflection of light in the transmissive areaTA of the first display area DA1 and reduce light loss when light istransmitted through the transmissive area TA of the first display areaDA1, it is necessary to reduce the middle width F of the ridge M.

After going through a general photolithography process, the ridge M canbe formed in a state where the middle width F of the ridge M is large.For example, after a general photolithography process, the ridge M witha small valley can be formed, and the ridge M having a large middlewidth F and a small slope S can be formed. The ridge M in this state hasmore diffuse reflection components and can decrease light efficiency.

Accordingly, after the photolithography process, by adding a frontexposure process to further crosslink the slope of the ridge M, thevalley of the ridge M can be deepened. For example, due to the additionof the front exposure process, the ridge M having a small middle width Fand a large slope S can be formed. Accordingly, the distance G betweenthe ridges M can also increase. Accordingly, diffuse reflection of theinsulating layer INS can be reduced, and light transmission capabilityof the insulating layer INS can be improved.

The insulating layer INS having the transmittance improving structureTIS as illustrated in FIGS. 12 and 13 can be one or more of a pluralityof insulating layers (MBUF, ABUF1, ABUF2, GI, ILD1, ILD2, PAS0, PLN1,PLN2, BANK, PAS1, PCL, PAS2, PAC) formed on the display panel 110.

For example, the insulating layer INS having the transmittance enhancingstructure TIS as illustrated in FIGS. 12 and 13 can include at least oneof a planarization layer PLN and a protective layer PAC. Theplanarization layer PLN can be disposed between the transistor layer TRLand the light emitting device layer EDL, and the protective layer PACcan be disposed on or over the touch sensor layer TSL.

FIGS. 14 and 15 are cross-sectional views of the display device 100according to embodiments of the present disclosure, and arecross-sectional views when the transmittance improving structure TIS isapplied in the transmissive area TA.

The stacked structure of FIGS. 14 and 15 is basically the same as thestacked structure of FIG. 6. However, the stacked structures of FIGS. 14and 15 further include a transmittance improving structure TIS in thetransmissive area TA.

Referring to FIG. 14, a plurality of insulating layers included in thedisplay panel 110 can include the buffer layers (MBUF, ABUF1, ABUF2)between the substrate SUB and the transistors (DRT, SCT), theplanarization layer PLN) between the transistors (DRT, SCT) and thelight emitting device ED), and the encapsulation layer ENCAP on thelight emitting device ED, etc.

As shown in FIG. 14, among the plurality of insulating layers, theplanarization layer PLN can include at least one uneven portion as atransmittance improving structure TIS in a portion overlapping thetransmissive area TA in the first display area DA1. Here, theplanarization layer PLN can be an organic insulating layer.

Referring to FIG. 14, the concave portion constituting at least oneuneven portion of the planarization layer PLN can pass through theinsulating layers ILD2, IDL1 and GI included in the transistor layer TRLand the buffer layer ABUF1, ABUF2 and MBUF positioned under theinsulating layers ILD2, IDL1 and GI, and can descend to the top of thesubstrate SUB. Accordingly, the upper surface of the substrate SUB isdepressed, so that at least one uneven portion can be formed in thesubstrate SUB as the transmittance improving structure TIS.

Referring to FIGS. 14 and 15, the first encapsulation layer PAS1 and thesecond encapsulation layer PCL included in the encapsulation layer ENCAPcan also have a transmittance improving structure TIS in a recessedform. Here, the first encapsulation layer PAS1 can be an inorganicinsulating layer, and the second encapsulation layer PCL can be anorganic insulating layer.

Referring to FIGS. 14 and 15, the protective layer PAC can be disposedto cover the touch sensor TS on the encapsulation layer ENCAP, so as toprotect the touch sensor TS.

As illustrated in FIG. 15, the protective layer PAC can have at leastone uneven portion as a transmittance improving structure TIS in aportion overlapping the transmissive area TA. Here, the protective layerPAC can be an organic insulating layer.

Referring to FIGS. 14 and 15, each of the plurality of touch sensors TScan be formed of a mesh-type touch sensor metal TSM. When the touchsensor metal TSM is formed in a mesh type, a plurality of open areas canexist in the touch sensor metal TSM of one touch sensor TS. The positionof each of the plurality of open areas can correspond to the position ofthe emission area of the subpixel SP.

The area of the touch sensor metals TSM per unit area in the firstdisplay area DA1 can be smaller than the area of the touch sensor metalTSM per unit area in the second display area DA2 so that thetransmittance of the first display area DA1 is higher than thetransmittance of the second display area DA2.

To this end, as shown in FIGS. 14 and 15, among at least onenon-transmissive area NTA and at least one transmissive area TA in thefirst display area DA1, the plurality of touch sensors TS can bedisposed in at least one non-transmissive area NTA, and the plurality oftouch sensors TS may not be disposed in the at least one transmissivearea TA.

FIG. 16 illustrates an arrangement of subpixels SP in the second displayarea DA2 of the display device 100 according to embodiments of thepresent disclosure. FIGS. 17A and 17B illustrate an arrangement ofsubpixels SP in the first display area DA1 of the display device 100according to embodiments of the present disclosure.

Referring to FIG. 16, the second display area DA2 can include a firstarea A1, a second area A2, a third area A3, and a fourth area A4. Eachof the first area A1, the second area A2, the third area A3, and thefourth area A4 can be a pixel area PA in the non-transmissive area NTAin which four subpixels SP (R, G, B, G) are disposed.

Referring to FIGS. 17A and 17B, the first display area DA1 can include afifth area A5, a sixth area A6, a seventh area A7, and an eighth areaA8. Among the fifth area A5, sixth area A6, seventh area A7, and eightharea A8, some areas (e.g., A5, A7) can be the non-transmissive areas NTAin which four subpixels SP (R, G, B, G) are disposed, and other areas(e.g., A6, A8) can be a transmissive area TA in which the subpixel SP isnot disposed.

Accordingly, the number of subpixels per unit area in the first displayarea DA1 can be smaller than the number of subpixels per unit area inthe second display area DA2. For example, the number of subpixels perunit area in the first display area DA1 can be ½ or ¼ of the number ofsubpixels per unit area in the second display area DA2. Accordingly, thetransmittance of the first display area DA1 can be higher thantransmittance of the second display area DA2. For example, thetransmittance of the first display area DA1 can be twice or four timesthe transmittance of the second display area DA2.

Referring to FIG. 17A, among the fifth area A5, the sixth area A6, theseventh area A7, and the eighth area A8, two areas A5 and A7 can be thenon-transmissive areas NTA and can be a pixel area PA in which foursubpixels SP (R, G, B, G) are disposed, and the other two areas A6 andA8 can be a transmissive area TA in which no subpixels SP are disposed.The area of each of the fifth area A5 and the seventh area A7, which isthe non-transmissive area NTA, can be smaller than the area of each ofthe sixth area A6 and the eighth area A8, which is the transmissive areaTA. The area of each of the fifth area A5 and the seventh area A7, whichis the non-transmissive area NTA in the first display area DA1, can besmaller than the area of each of the first to fourth areas A1 to A4,which is the non-transmissive area NTA in the second display area DA2.

In this case, the number of subpixels per unit area in the first displayarea DA1 can be ½ of the number of subpixels per unit area in the seconddisplay area DA2. The transmittance of the first display area DA1 can betwice or more times the transmittance of the second display area DA2.

Referring to FIG. 17B, among the fifth area A5, the sixth area A6, theseventh area A7, and the eighth area A8, one areas A5 can be thenon-transmissive areas NTA and can be a pixel area PA in which foursubpixels SP (R, G, B, G) are disposed, and the other three areas A6, A7and A8 can be a transmissive area TA in which no subpixels SP aredisposed. The area of the fifth area A5, which is the non-transmissivearea NTA, can be the same as the area of each of the sixth area A6, theseventh area A7, and the eighth area A8, which are the transmissiveareas TA.

In this case, the number of subpixels per unit area in the first displayarea DA1 can be ¼ of the number of subpixels per unit area in the seconddisplay area DA2. The transmittance of the first display area DA1 can befour times of the transmittance of the second display area DA2.

According to embodiments of the present disclosure, the display device100 in which a light receiving device 120 (e.g., camera, proximitysensor, etc.) is positioned behind the display panel 110 can be providedso that the light receiving device 120 that should receive light fromthe front is not exposed to the front.

According to embodiments of the present disclosure, even if the lightreceiving device 120 is positioned behind the display panel 120, it ispossible to provide the display device 100 in which light from the frontsurface of the display panel 110 can be well transmitted to the lightreceiving device 120 through the display panel 110.

According to embodiments of the present disclosure, it is possible toprovide the display device 100 having a higher transmittance in thedisplay panel 110 in a region overlapping with the light receivingdevice 120 compared to other regions.

According to embodiments of the present disclosure, the display device100 in which a transmittance improving structure is formed in a regionoverlapping with the light receiving device 120 in the display panel 100can be provided.

The above description has been presented to enable any person skilled inthe art to make and use the technical idea of the present disclosure,and has been provided in the context of a particular application and itsrequirements. Various modifications, additions and substitutions to thedescribed embodiments will be readily apparent to those skilled in theart, and the general principles defined herein can be applied to otherembodiments and applications without departing from the spirit and scopeof the present disclosure. The above description and the accompanyingdrawings provide an example of the technical idea of the presentdisclosure for illustrative purposes only. For example, the disclosedembodiments are intended to illustrate the scope of the technical ideaof the present disclosure. Thus, the scope of the present disclosure isnot limited to the embodiments shown, but is to be accorded the widestscope consistent with the claims. The scope of protection of the presentdisclosure should be construed based on the following claims, and alltechnical ideas within the scope of equivalents thereof should beconstrued as being included within the scope of the present disclosure.

What is claimed is:
 1. A display device comprising: a display panelincluding a substrate and a plurality of insulating layers, a transistorlayer, and a light emitting device layer on the substrate, the displaypanel including a display area in which an image is displayed, thedisplay area including a first display area and a second display area;and a light receiving device positioned behind the display panel andoverlapping with the first display area, wherein the number of subpixelsper unit area in the first display area is smaller than the number ofsubpixels per unit area in the second display area, wherein the firstdisplay area includes at least one non-transmissive area in whichtransistors of the transistor layer and light emitting devices of thelight emitting device layer are located, and at least one transmissivearea through which external light is transmitted to the light receivingdevice, and wherein the substrate or at least one insulating layer amongthe plurality of insulating layers includes at least one hole or atleast one uneven portion in a portion overlapping the at least onetransmissive area.
 2. The display device according to claim 1, whereinthe at least one uneven portion is formed on a rear surface of thesubstrate, and a portion of the substrate that overlaps the at least onetransmissive area includes at least one raised rear surface.
 3. Thedisplay device according to claim 2, further comprising a transparentmaterial layer disposed under the at least one raised rear surface ofthe substrate.
 4. The display device according to claim 1, wherein theat least one uneven portion is formed on an upper surface of thesubstrate, and a portion of the substrate that overlaps the at least onetransmissive area includes at least one recessed upper surface.
 5. Thedisplay device according to claim 1, wherein the substrate includes afirst substrate, an interlayer insulating layer on the first substrate,and a second substrate on the interlayer insulating layer, and whereinthe at least one uneven portion is formed on a rear surface of the firstsubstrate, and a portion of the first substrate that overlaps the atleast one transmissive area includes at least one raised rear surface.6. The display device according to claim 5, further comprising atransparent material layer disposed under the at least one raised rearsurface of the first substrate.
 7. The display device according to claim1, wherein the substrate includes a first substrate, an interlayerinsulating layer on the first substrate, and a second substrate on theinterlayer insulating layer, and wherein the at least one uneven portionis formed on an upper surface of the second substrate, and a portion ofthe second substrate that overlaps the at least one transmissive areaincludes at least one recessed upper surface or the at least one hole.8. The display device according to claim 1, wherein the plurality ofinsulating layers comprise: a buffer layer between the substrate and thetransistor layer; a planarization layer between the transistor layer andthe light emitting device layer; and an encapsulation layer on the lightemitting device layer, and wherein the planarization layer includes theat least one uneven portion at a portion overlapping the at least onetransmissive area in the first display area.
 9. The display deviceaccording to claim 8, wherein a concave portion constituting the atleast one uneven portion of the planarization layer passes through theinsulating layers included in the transistor layer and the buffer layerpositioned under the insulating layers and descends to the upper portionof the substrate.
 10. The display device according to claim 8, whereinthe display panel further includes a plurality of touch sensors disposedon the encapsulation layer, and a protective layer on the plurality oftouch sensors, and wherein the protective layer includes at least oneuneven portion at a portion overlapping the at least one transmissivearea.
 11. The display device according to claim 10, wherein theplurality of touch sensors include mesh-type touch sensor metals, and anarea of the touch sensor metals per unit area in the first display areais smaller than an area of the touch sensor metals per unit area in thesecond display area.
 12. The display device according to claim 10,wherein among the at least one non-transmissive area and the at leastone transmissive area in the first display area, the plurality of touchsensors are disposed in the at least one non-transmissive area and theplurality of touch sensors are not disposed in the at least onetransmissive area.
 13. The display device according to claim 1, whereinthe at least one insulating layer includes an organic insulatingmaterial.
 14. The display device according to claim 1, wherein the atleast one insulating layer includes a photosensitive material.
 15. Thedisplay device according to claim 1, wherein the substrate includes anon-photosensitive material.
 16. The display device according to claim1, wherein a shape or size of a concave-convex portion in a portionwhere the substrate overlaps the at least one transmissive area, and ashape or size of a concave-convex portion in a portion where the atleast one insulating layer overlaps the at least one transmissive areaare different from each other.
 17. The display device according to claim1, wherein the second display area includes a first area, a second area,a third area, and a fourth area, wherein each of the first area, thesecond area, the third area, and the fourth area is the at least onenon-transmissive area in which four subpixels are disposed, wherein thefirst display area includes a fifth area, a sixth area, a seventh area,and an eighth area, wherein areas of the fifth area, the sixth area, theseventh area, and the eighth area correspond to areas of the first area,the second area, the third area, and the fourth area, and wherein amongthe fifth area, the sixth area, the seventh area, and the eighth area,some areas are the at least one non-transmissive area in which foursubpixels are disposed, and another partial area is the at least onetransmissive area in which no subpixels are disposed.
 18. The displaydevice according to claim 1, wherein the number of subpixels per unitarea in the first display area is about ½ or ¼ of the number ofsubpixels per unit area in the second display area.
 19. The displaydevice according to claim 1, wherein the light receiving device includesat least one of a camera and a proximity sensor, and the light receivingdevice is not exposed on a front surface of the display device.
 20. Adisplay device comprising: a display panel including a substrate and aplurality of insulating layers, a transistor layer, and a light emittingdevice layer on the substrate, the display panel including a displayarea in which an image is displayed, the display area including a firstdisplay area and a second display area; and a light receiving devicepositioned behind the display panel and overlapping with the firstdisplay area, wherein the number of subpixels per unit area in the firstdisplay area is smaller than the number of subpixels per unit area inthe second display area, wherein the first display area includes atleast one non-transmissive area in which transistors of the transistorlayer and light emitting devices of the light emitting device layer arelocated, and at least one transmissive area through which external lightis transmitted to the light receiving device, and wherein the substrateor at least one of the plurality of insulating layers has a variablethickness in a portion overlapping the at least one transmissive area.